FDA Draft Guidance on Bayesian Methodology in Drug Trials

Detected February 6th, 2026

Summary

The FDA has issued draft guidance on the use of Bayesian methodology in clinical trials for drug and biological products. This guidance is intended for sponsors and applicants and focuses on supporting primary inference for effectiveness and safety. The agency is seeking public comments on this draft document.

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The FDA has released draft guidance (Docket Number: FDA-2025-D-3217) for sponsors and applicants regarding the appropriate use of Bayesian methods in clinical trials for drug and biological products. The guidance specifically addresses how these methods can be employed to support primary inference for demonstrating the effectiveness and safety of new drugs and biologics, and it is relevant for Investigational New Drug (IND) applications, New Drug Applications (NDAs), and Biologics Licensing Applications (BLAs).

This document is a draft and is open for public comment. Interested parties, including drug and pharmaceutical companies, can submit comments online through regulations.gov or via mail. The FDA is seeking input to refine its recommendations on the application of Bayesian statistics in drug development. While this guidance is non-binding, it represents the agency's current thinking and will inform future regulatory submissions.

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Docket Number: FDA-2025-D-3217 Issued by: Guidance Issuing Office Center for Biologics Evaluation and Research Center for Drug Evaluation and Research This draft guidance provides guidance to sponsors and applicants submitting investigational new drug applications (INDs), new drug applications (NDAs), biologics licensing applications (BLAs), or supplemental applications on the appropriate use of Bayesian methods in clinical trials. Bayesian methods can be used in various ways in clinical trials. For example, Bayesian calculations can be used to govern the timing and adaptation rules for an interim analysis in an adaptive design, to inform design elements (e.g., dose selection) for subsequent clinical trials, or to support primary inference in a trial. The primary focus of this guidance is on the use of Bayesian methods to support primary inference in clinical trials intended to support the effectiveness and safety of drugs.